Sail



April 20, 1937. w. F. GERHARDT SAIL Filed' April 18, 1934 NVENTR.

ATTORNEYS Patented Apr. 20, 1937 UNITED STATES PATENT OFFICE Claims.

My invention relates to sails or means of propulsion which utilize thewind, and in particular it relates to the construction and dispositionof the sail elements in a manner which results in the attainment of anunusual degree of efciency.

For a great number of years very little development or improvements havebeen made in means for propelling water craft by wind velocities. Inconsideration that Water crafts are dependent upon the natural elementsfor their propulsion I provide a sail wherein its combined features haveshown a decided improvement over any conventional type of propulsionmeans dependent upon 15 the natural elements.

It is an object of my invention to dispose the sail canvas Ato windvelocities in the most suitable manner. Another object is to constructthe sail in a manner so as to obtain substantially the maximum reductionin air resistance.

Another object is that, in comparison, a craft utilizing a sail of myinvention is capable of ay greater speed, with a sail of the sameprojected area than a similar craft carrying a conventional sail, or Imay reduce the projected area of canvas in my sail and still retain thesame reaction to wind velocities by propelling a craft carrying my sailat the same speed as'a similar craft carrying a conventional sail ofgreater area.

Another object is that I am able to maintain the sail canvas at auniform angle relative to the wind, and a further object is that a craftcarrying the sail of my invention is capable of progressing at a lesserangle against the wind than crafts carrying conventional sails.

Another object is the elimination of the conventional boom, which is amatter of great convenience both to operators and/or passengers of watercrafts. Furthermore, the width of the sail or boom length does notgenerally extend beyond the beam of the vessel.

A further object is that the sail angle may be conveniently controlledby rotary movement of the mast. A still further object is to providetensioning means for controlling the curvature of the sail comprising anair foil so that such curvature may provide the correct air foil fordifferent wind velocities. Other objects are that it is generally notnecessary to lower the sail nor is it generally necessary to reef thesail.

These and other objects and advantages will appear more fully in thefollowing detailed description when considered in connection with theaccompanying drawing in which:

Figure 1 is a side elevational view partly in section of an embodimentof my invention.

Figure 2 is a plan view of means for controlling radial movement o-f themast taken along lines II-II of Figure 1.

Figure 3 is a plan View partly in section of a sail strut taken alonglines III- III of Figure 1.

Figure 4 is a somewhat similar view as that shown in Figure 3exemplifying a modication of the sail strut.

Figure 5 is a transverse view in section of the sail foil taken alonglines V-V of Figure 1.

Figure 6 is a side elevational View of a water craft carrying the sailof my invention.

Figure 7 is a comparative view in side elevation of a conventional Watercraft carrying a conventional sail.

Figure 8 is a plan view of a boat and sail of my invention, and

Figure 9 is a comparative illustration in plan iew of a similar boatcarrying a conventional sail.

With reference to Figure 1, I show an embodii ment of my inventioncomprising a mast l and a sail canvas 2. As a support for the sailcanvas I provide a plurality of struts 3 in substantial parallelism andat right angles to the mast l. A rope or cord 4 extends around thepulley 5 attached to the mast l and is threaded through apertures 6(Figure 3) at the outer ends of each of the struts 3. From the lowermoststrut 3 the cord 4 is attached to some means on the mast such as acleat 1. The opposite end of the cord 4, after it passes through pulley5, may extend downwardly and become attached to any convenient means onthe boat or at the lowermost part of the mast.

The structure thus far described provides an outline frame work uponwhich the sail canvas 2 is retained. In transverse section and as shownin Figure 5, the sail canvas 2 is in the form of a sleeve or envelopesuspended between the mast l and the cord 4 supported by the struts 3.The sail canvas merely `loops around the mast and is not attachedthereto. fIhe sail canvas is, therefore, free to adjust itself to properair foil shape according to wind direction. In other words, if the sailis permitted to adjust itself freely according to the direction of theWind, the sail canvas will assume an outline of substantially straightside surfaces tapering from the mast tothe cord 4. On the other hand, atransverse section of the sail will assume an arcuate foil shape whenthe sail is held in angular relation with the Wind direction.

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In order to provide the proper degree of tensioning for the air foil,the cord 4 is made adjustable as by drawing it tighter or permittingmore slack in the cord 4 in its attachment to the cleat 1. Ifpreferable, the opposite end of the cord 4 may provide the adjustablemeans for controlling the tension of the air foil by any conventionalmeans of attachment of the cord 4 to the deck or other part of the boat.

By providing tensioning means for adjusting the air foil it is possibleto obtain the greatest eiiciency of the sail in accordance with low orhigh wind velocities. In other words, where the wind velocity is low itmay be preferable to slack the cord 4 so as toi provide an increasedarcuate curvature of the foil. On the other hand, when the windvelocities are high it may be preferable to increase the tension on thecord 4 and thus reduce the curvature of the foil shown in Figure 5.

As a general rule, it is not particularly essential to take down thesail while the boat is not in operation for reason that when the sail ispermitted to adjust itself freely with respect to the direction of thewind, the sail of my invention provides less resistance than a mastalone. However, for purposes of convenience, I provide means forlowering the sail canvas. In order to accomplish this, I provide channelstrips 8 and 9 extending longitudinally of the mast I and attachedthereto. The channel strips 8 and 9 thus form a slideway for the struts3. Furthermore, these channel strips 8 and 9 have inwardly turnedmarginal portions IB which associate with complementary depressions inthe base of the struts 3. In this manner the struts 3 are held atsubstantial right angles to the mast I and are prevented from movingradially of the mast. In other words, the struts 3 are restricted tolongitudinal sliding movement relative to the mast I.

In order to properly space the struts 3 and to retain them in properspaced relation, I provide a cord i I attached to an eye I2 which inturn is attached to the mast I. The opposite end of the cord II isattached to the under side of lowermost strut 3. Any convenient mode forfacilitating the attachment may be used, such as a screw-eye I3. In asimilar manner a short length of cord I4 attaches each of the strutstogether in spaced relation. The cord I5 extending from the uppermoststrut 3 passes around a pulley I6 attached to the mast I and returnsdownward to the deck of the boat where it may be attached in anyconvenient manner. It may, therefore, be seen that by releasing the cordI5 together with the cord 4 in their attachment to the deck of the boat,the sail together with the struts may be lowered to form a convenientand compact bundle at the lower portion of the mast.

While I have shown one form of raising or lowering the sail it is to beunderstood that this may be accomplished in other methods. For example,as shown in Figure 4, I may attach struts I1 to a mast I8 in a hingedmanner as by providing a collar clamp I9 around the mast in a manner soas to provide outwardly extending lugs 20 for coi-operative engagementwith the base of the strut I'I. A pin 2| extending through the lugs 2E)of the collar I9 and through the base end of the strut I1 provides thedesired hinged effect. In this method of collapsing the sail, the collarclamps I9 remain permanently attached to the mast I and upon release ofone end of the cord, as 4, the struts may be folded in parallel relationwith the mast. The sail canvas is thus carried along with the struts toform a compact bundle along the length of the mast.

As shown in Figure 3, I prefer that the struts S have their sidesurfaces in the form of a concave arcuate outline extending at its baseend substantially tangent to the mast and being substantially thinner atits opposite end. The purpose of the concave outline of the struts 3 isto supply as near as possible a strut which will conform to the true airfoil shape assumed by the sail canvas which encases the struts.Therefore, the presence of the struts does not interfere materially indistorting the true assumed air Ioil shape of the canvas. It isunderstood, of course, that in the event the struts do form slightinterference with the air foil shape of the canvas, such interference islocalized only at those regions where the struts are located. However,the back of the sail, with respect to the wind direction, is free fromany projections resulting from the struts, and, as the back of the sailis the most important as far as the propulsion of the ship is concerned,it may be said that the sail throughout its entire area is positioned insubstantially the most efficient manner for reaction with windvelocities. n As before stated, the sail of my invention requires meansfor rotatably moving the mast so as to dispose the sail in properrelation with the wind direction. In Figure l, I show the mast Iextending through a portion of the boat structure, such as the deck 22.A iiange 23 is preferably attached to the deck 22 to operate as asupporting bushing for the mast I. The extreme lowermost portion of themast I is also provided f with means (not shown) for rotatablysupporting the mast. Beneath the deck 22 a worm gear 24 is attached tothe mast I and co-operates with a worm pinion 25 keyed to a shaft 26.

As shown particularly in Figure 2 the shaft 2 6 is supported by brackets2'! and 23. The bracket 21 is pivoted to the deck 22 While the oppositebracket 2S is free from permanent attachment to the deck 22. The purposeof the pivoted bracket arrangement is to provide means for quicklydisengaging the worm with the worm gear 24 so as to permit the mastcarrying the sail to move freely according to the direction of the wind.

When the worm 25 is brought into engagement with the worm gear 24 thebracket 28 engages on one side with a depending arm attached to the deck22 while the opposite side of the bracket 2S may be associated with acornplementary pivoted arm 3| hingedly attached to the deck 22 at 32.Movement of this pivoted arm may be eifected by manual operation of ahand lever 33 extending integrally from the pivoted arm 3| A hand wheel35 attached to the shaft 26 supplies means for manual rotation of theworm 25 and the resultant control of the sail angle.

As shown in Figure 2, the various elements are in proper position formanual control of the sail angle. However, when it is desired to permitthe sail to move freely with the wind it is only necessary for theoperator to grasp and move the hand lever 33 so as to move the pivotedarm 3| out of engagement with the bracket 28. The assembly may then beswung on the pivot 29 so that the hand wheel 35 assumes a position suchas that shown by 36. This operates to disengage the worm 25 with theworm gear 24, thus removing all positive control from the mast I.

While the foregoing method of controlling the comparative with that ofFigure 7 which shows a similar water craft 39 carrying, however, aconventional sail 40 of the Marconi type. Sail 40 may, however, alsorepresent the gall type sail.

In these comparative views I intend that the projected area of sail 38should be substantially equal to the projected area of the sail 40.

In Figure 6, the character X represents a distance from the water levelto the center of the area of the sail 38, whereas Y represents adistance from the water level tothe center of the area, of the sail 40.It is a generally known fact that the wind velocity varies according tothe heights from the water level. In other words, the Wind velocity iszero at the water level and attains its maximum velocity at about 50feet above water level.

It has been demonstrated that, assuming there is a twelve miles per hourwind velocity, the eiective velocity at a height represented by thedistance X shows ten miles per hour wind velocity, whereas the heightrepresented by Y in Figure 7 shows a wind velocity of but eight milesper hour. Therefore, by comparative disposition of the outline of thesail only, I am able to attain a greater benefit from wind velocities.

Figures 8 and 9 represent plan views of Figures 6 and 7 respectively. InFigure 8, the arrow W represents the direction of the wind, and the boat31 is shown inclined at an angle of which it is capable of proceedingagainst the wind. It has been demonstrated that when the sail ispositioned substantially at 'l degrees relative toi the keel of theboat, the boat is capable of progressing against the wind at an angle of17 degrees relative thereto.

In comparison with the boat 39 shown in Figure 9, the conventional sail40 is generally incapable of progressing the boat at a lesser angle than3U degrees into the wind. In such case the boom 4| is positioned atabout 5 degrees relative to the keel of the boat. The hypothenuse of thesail 40 assumes a curved line 4I thus showing that the angles of theconventional sail are numerous. For example, when the boom is disposed 5degrees relative to the keel, the diierential angularity of the topportion of the sail frequently varies as much as 90 degrees.

These comparative Figures 8 and 9 have for their purpose to show thatthe sail of my invention is throughout its area correctly positioned inangular relation to the Wind while the conventional sail assumes variousangles from the boom to the uppermost area of the sail. This is ofconsiderable importance when it is definitely known that in order toobtain the greatest efficiency from a sail, it is highly desirable thatthe entire surface area of the sail should be correctly positioned indefinite angular position with the wind.

It may, therefore, be seen that in combination with the true air foiltransverse shape of my sail, with its comparative disposition in sideelevational outline, and together with its capability of retaining asubstantially uniform plane throughout its area, I have attained a sailof much greater eniciency than any heretofore conventional sail ofpractical design.

y While I have shown a present preferred embodiment of my invention, itis to be understood that I contemplate within the scope of my inventionall those changes which are obvious except as limited by the scope oithe appended claims.

Having thus described my invention what 1 claim is:

l. In a sail of the character described, a mast, a plurality of strutshingedly attached to said mast and extending substantially at rightangles therefrom and in a single plane, means attached to the ends ofthe struts opposite the mast to define with the mast a substantiallyrigid trapezoidal outline, and a canvas envelope loosely supported bythe leading portion of said mast and enclosing the mast, and saidstruts.

2. In a sail of the character described, a mast, a plurality of strutsextending from the mast at substantially right angles therefrom and in asingle plane and a'canvas envelope loosely supported by the leadingportion of said mast and enclosing the mast and struts, said strutsbeing longitudinally slidable relative to said mast.

3. In a sail of the character described, a mast, a plurality of strutsin a single plane and in spaced relation extending from the mast and inslidable relation therewith, a canvas envelope loosely supported by theleading portion of said mast and enclosing the mast and struts, andmeans attached to each of the struts for holding same in spacedrelation.

4. In a sail, a mast, struts extending in a single plane from said mast,means connecting the ends of the struts opposite said mast, and a canvasenvelope in contact relation with the leading portion of said mast andenclosing the mast and said struts.

5. In a sail, a mast, a sail canvas looped around the mast and incontact relation with the leading portion thereof to form an air foil, aplurality of struts in a single plane and in spaced relation extendingfrom the mast and within the air foil, and means for connecting the endsof the struts opposite the mast, the air foil formed by said canvashaving a cross-sectional outline at its leading portion substantiallyequal to the width of the mast and decreasing in width to a feather edgeat the aft end of the cross-sectional outline.

6. In a sail, a mast, a sail canvas looped around the mast and incontact relation with the leading portion thereof to form an air foil oftear-drop shape, a plurality of struts in a single plane and in spacedrelation extending from the mast and within the air foil, and means forconnecting the ends of the struts opposite the mast, said struts beingattached to said mast in a manner so that they will pivot in asubstantially parallel relation with the mast.

7. In a sail, a mast, a plurality of struts in a single plane and inspaced relation extending substantially at right angles from the mast, acanvas envelope looped around the mast and in contact relation with theleading portion thereof and enclosing mast and struts, and means forrotatably moving the mast.

8. In a sail, a mast, a plurality of struts in a single plane and inspaced relation extending substantially at right angles from the mast, acanvas envelope looped around the mast and in contact relation with theleading portion thereof and enclosing the mast and struts, means forrotatably moving the mast, and means for restricting rotary movement ofthe mast due to Wind force against the sail.

9. In a sail, a mast, a plurality of struts in a single plane and inspaced relation extending substantially at right angles from the mast,acanvas envelope looped around the mast and in contact relation with theleading portion thereof and enclosing the mast and struts, means forrotatably moving the mast, and means for detaching the latter means topermit free movement of the mast.

10. In a sail, a mast, a plurality of struts in a single plane only andin spaced relation extending from the mast, a canvas envelope loopedaround the mast and in contact relation with the leading portion thereofand enclosing the mast and struts, said struts being rigidly attached tothe mast.

11. A sail comprising a mast, a support spaced aft of the mast, and asail-canvas forming an envelope Vinclosing the mast and support, saidcanvas being in contact relation With the leading portion of said mast.

12. A sail comprising a mast, a support spaced aft of the mast, and asail-canvas looped around the mast in contact relation With the leadingpor tion thereof and joined together substantially at and attached tosaid support.

13. A sail comprising a mast, a support spaced aft of the mast, asail-canvas looped around the mast in contact relation With the leadingportion thereof and joined together substantially at and attached tosaid support, and struts extending from the mast for maintaining saidsupport in spaced relation With the mast.

14. A sail comprising a mast, a support spaced aft of the mast, asail-canvas looped around the mast in Contact relation with the leadingportion thereof and joined together substantially at and attached tosaid support, struts extending from the mast for maintaining saidsupport in spaced relation With the mast, and means for adjusting thetension of said support.

l5. In a sail, the combination of a mast, a sailcanvas in the form of anenvelope looped around the mast and in contact relation with the leadingportion thereof and comprising two Wings spaced apart at the mast andjoined together at a considerable distance aft from the mast, and strutswithin the canvas envelope and attached to the mast for supporting theait end of the canvas envelope.

WILLIAM F. GERHARDT.

